MoS2 Field-effect Transistors with Graphene/Metal Heterocontacts

TL;DR

This paper reports the fabrication of n-type MoS2 transistors with graphene/Ti hetero-contacts, demonstrating significant improvements in electrical performance and providing insights into contact resistance and Schottky barrier characteristics.

Contribution

It introduces a novel hetero-contact structure for MoS2 transistors and analyzes its electrical properties and contact mechanisms using new measurement methods.

Findings

Over 160 mA/mm drain current at 1 μm gate length

2.1 times reduction in on-resistance

3.3 times reduction in contact resistance

Abstract

For the first time, n-type few-layer MoS2 field-effect transistors with graphene/Ti as the hetero-contacts have been fabricated, showing more than 160 mA/mm drain current at 1 {\mu}m gate length with an on-off current ratio of 107. The enhanced electrical characteristic is confirmed in a nearly 2.1 times improvement in on-resistance and a 3.3 times improvement in contact resistance with hetero-contacts compared to the MoS2 FETs without graphene contact layer. Temperature dependent study on MoS2/graphene hetero-contacts has been also performed, still unveiling its Schottky contact nature. Transfer length method and a devised I-V method have been introduced to study the contact resistance and Schottky barrier height in MoS2/graphene /metal hetero-contacts structure.